Introduction to Images and Pixels

So let’s look at the code that works on an image or a picture. First thing you have to do of course is import the image library that defines the classes that we’re using to create images. Then we can create an image object. So from a file name, so arch.jpg, then we can ask the image to give us a list of all of its pixels. So we get a list of pixel objects. So images have pixels. And we can loop through the pixel list. So for P in pixel list. And we can set the pixels’ red. So using setRed of zero. And then we can update the pixel and the image.

So we’ve changed the red but we also have to update the image. And then we can show the result by getting a window and drawing the image in that window. And when we do that, because we’re setting the red to zero, what we’re going to see in a moment, takes a little bit of time, is that the original arch looks like it’s being seen through a green filter because what we’ve done is reduce the red so it looks more blue-greeny. This is sort of how water works. Water reduces the amount of red light that comes through so that’s why water looks blue-green. So that’s a little bit about images.